Annular radiating drum air heating furnace



H. H. DIGGINS ANNULAR RADIATING DRUM AIR HEATING FURNACE Filed July 17, 1948 Sept. 18, 1951 2 Sheets-Sheet l K "away. M i- W,

' H. H. DIGGINS ANNULAR RADIATING DRUM AI R HEATING FURNACE Filed July 17, 1948' Sept. 18, 1951 2 Sheets-Sheet 2 Patented Sept. 18, 1951 ANNULAR RADIATING DRUM Am HEATING FURNACE 1 Harte H. Diggins, Woodstock, Ill.

Application July 17, 1948, Serial No. 39,231

1 Claim.

The presentinvention relates to the art of heating space by means of hot or warm air; and

v supply central heat for whole dwellings and other large spaces.

In carrying out my invention I use sheet metal for all of the main parts except, ofcourse, the burner, and unite them by crimping meeting marginal portions of the sheets in any conventional manner. Therefore, viewed in one of its aspects, the present invention may be said to have for its object to create a heater of any desired capacity from material comparable to that used in ordinary stove pipes, for example, and having its joints made mainly or entirely by crimping the said sheet metal.

The various features of novelty whereby the present invention is characterized will hereinafter be pointed out with particularity in the claim, but, for a full understanding of the invention and of its objects and advantages, ref: erence may be had to the following detailed de-' scription taken in connection with the accompanying drawings, wherein:

Figure 1 is a front elevation of a heater of one of the larger sizes embodying the present invention; Fig. 2 is a rear view of the heater; Fig. 3 is a top plan View of the heater; Fig. 4 is a vertical section through the heater, on a somewhat larger scale than Figs. 1-3; Fig. 5 is a section on line 5-5 of Fig. 4; Fig. 6 is a section, on a still larger scale, showing the conventional stove pipe seam used in the various shells which may be one taken on line 6-6 of Fig. 4 or of Fig. 12, for example; Fig. '7 is a section through a second form of seam, used in connecting the flaring ends In the particularheater shown in the drawings there are five coaxial cylindrical shells. The inner shell I forms the body of the fire tube; the next smaller, shell}, is adapted to absorb radiant heat from the fire tube; the next two shells, 3 and 4, are connected together, as will be explained later, to form an annular drum into which the combustion gases pass before leaving the heater; and the outermost shell 5 absorbs heat radiated from the drum. Radiant shell 2 also absorbs some of the heat radiated from the drum. The radiant shell 2 is preferably the longest, extending well below the others, and the radial distance between the same and the fire tube is preferably about twice as great as the corresponding distance between the same and the drum. The top of shell I is closed by a cap 6 that decreases in cross sectional area from the base to the top; the shape illustrated being conical.

Each shell is made from a single sheet rolled into the form of a cylinder, with meeting edges joined by a conventional stove pipeseam 1, as shown in Fig. 6.

The inner shell member 3 of the drum is shorter than the outer one, 4, corresponding ends being connected together by flaring band-like ring sections 8, 8. The joints between shells 3 and 4 and these ring sections are illustrated in 1 whereas the lower end of shell 4 is simply of the inner shell member of the annular drumj Fig.8 is a View similar to Fig. '7, showing the seam between the flaring part in Fig. 7 and the outer of the two shells that form the drum; Fig. 9 is a transverse section through a corner of the heater casing; Fig. 10 is an elevational view of the cap for'the fire tube before assembly on the latter, a

portion being broken away; Fig. 11 is an elevational view of one of the halves of which the cap is made, before the halves are joined together; Fig. 12 is an elevation view of one of the exhaust' tubes before being assembled in the heater; and

Fig. 13 is an elevational view of one of the passovers for the hot combustion gases, ready for assembly inthe heater.

crimped, as at 4, to embrace the lower flange 8* The fire tube, drum, and intermediate radiant shell are shown as being held together by three like tubular pass-overs 9; these being oval in cross section and being assembled in the structure with their long transverse axes vertical. The

' pass-overs are like pieces of stove pipe, each containing the conventional stove-pipe seam as shown in Fig. 13, and each being provided with external beads ID and. II a short distance from its ends. Shells I, Zand 3 contain registering holes through which the pass-overs extend; shells I and 3 abutting against beads l0 and H, respecpipe, not shown.

loose on the pass-overs, but is held in axial alignment by spacers l2, interposed between the same and shell 3. Shell is connected to shell 4 by means of intermediate members [6.

Two of the pass-overs are near the top of the fire tube, diametrically opposite each other, while the third is near the bottom with its longitudinal axis at right angles to a vertical plane containing the corresponding :axes of the upper pass-overs.

The combustion gasses flow from the fire tube into the drum through the pass-overs, and escape from the drum through two like exhaust tubes l4, [4 of which one is shown in detail .in Fig. .12.

It will be seen that the draft tube and burner housing is divided into upper and lower compartments by a horizontal partition 34. The burner 35, shown only in outline in broken lines, extends through the partition so that air may be supplied to the burner through the lower compartment and to the flame through the upper compartment.

The heater casing has in the front wall, above the door .24, a panel 36 interlocked with the two vertical side members of the casing by means of joints 31, shown in detail in Fig. 9. There is a similar panel 38 in the rear side of the casing 0r pabinet. but extending throughout the entire height of the latter. Top and bottom walls I9 and I9 respectively, having crimped connections with the vertical walls, complete the cabinet.

from the bead. Two openings, .arrangedclose to- V gether, are provided in the shell member 4 of the drum, diametrically opposite the lower pass-over, but somewhat lower down, for the reception of the :marginal portions M iof the exhaust tubes; these marginal'portions being then flanged later- ;ally i011 the inner side of shell 4 ;to fix the exhaust tubes to the shell. The exhaust tubes pass through holes in the outer shell 5 :so :that, when spacers 16 are placed between that shell :and shell 4, as shown in Fig. ;5, shell 511s locked in its ,proper position .relative :to the other shells.

.Ihe fire tube .fits at its lower end -.over a short sleeve section I! constituting :an outlet through the top of .a combined draft tube and burner housing 13, close to one .end of the latter; such z'housing being a rectangular box-alike structure open at the end that projects farthest beyond the the tube, namely the right hand end in Fig. 4. The :lower end of theradia'ntshell :2 partially embraces :the part of housing 418 that becomes hot, :so as :to absorb some of the radiant heat emitted :fromithe latter.

The unit heretofore described is housed in a cabinet or casing 19 that isrsquare, with rounded :corners, 'incross section, and is made from .sheet .metal without extraneous Lfastenings. The two exhaust tubes I4 extend through the rear wall of this casing into a draft vdiverter 20 which is simply .a little :housing open at :the :bottom and having in the top an .outlet opening surrounded by a short sleeve-like part 2| to receive 'a fine This outlet, :as best shown in Fig. 5, has its center on a radius bisecting the angle between the exhaust tubes and outwardly from the ends of these tubes; whereby any Lback draft will go straight down past these tubes and not through them into the heater. The casing has louvers 2'2 in the lower part of the rear wall and has in the lower part of the front side a door '24 containing louvers the door giving access to the interior of the draft tube and burner housing when removed as in Fig. 4. The top wall of the casing is provided with projecting sleeve-like :elements upon which may be slipped pipes for carrying heated air to spaces to be heated. There may be any desired number of these elements, =five of them, 2-6, 21, '28, Hand being shown.

The front end of the combined-drait'tube and burner housing may be fastened to or be supported by the walls-of the-casing in any suitable manner. In the arrangement shown, there is a transverse ang-le' bar 3-l fastened to the top of this housing and, "in 'turn, to the front wall of the heater casing :above the door opening. There is also a support :32 below the housing, this supside walls of :the casing.

.Asheretofore explained, the cap 5 on the fire tube may be of any desired shape and construction. In the arrangement shown in Fig. 10 and Fig. 11, it is formed of two sheet metal half cones .6 that meet in ;a :plane containing the :axis .of the cone. At their meeting edges are rflanges 139 that may be welded together .or :be crimped :to produce a :seam 40. .A flange or short skirt All along the lower edge adapts the cap for attachment to the shell member of the fi'lbliube.

It will thus be seen that .I have produced a very simple heater composed of a complete heat interchange unit and .a separate sdra'ft tube and burner housing that are readily assembled in a casing which, like the rest of the structure i made from sheet metal; .50 that {it is an .easy :matter :to build a heater of any desired capacity .at :a :minimum cost in it'll-m6, llabQr andmaterial. Because there are three annular layers of air that are heated either {by :direct Contact with ,or :radiation fromsurfaces heated directly bythe fire or hot .combustion gases, and -.a :fourth annular layer, just inside the heater peeing. athatzflows past a surface that has received radiant heat ;from one of the aforesaid surfaces: there is a :maximum transfer of heat from the source vto the air .to insure high efliciencyr; and the temsPerature :of the heater'rcasing is kept low. It

also '-be;se en that, because of the two separate sources of supplying :air :ior supporting .combustion and the easy access to the burner and :its controls, it is a simple matter to :achieve a high :degree of efiiciency :in the combustion of .tuel.

It should further be noted that the flaring 1 inlet for the annularairspace immediately surthe :parts .of the heater.

rounded :by the :drum insures that more air will rise through this space than would otherwise be the ease; and :that :the flaring outlet for this :annular .space and the :conical cap on the -fire tube permit ready expansion :of :the heated air leawing the innerannular spaces and approaching *the :distributing .pipes.

A ver important feature of "my invention resides in 'the manner of making and assembling The five shells, the tu- Beular ipassaovers and :the exhaust tubes are out ;to pattern from flat sheet material, and :the required openings are provided therein. .The fiat sheets are then rolled into their intended cylindrical or :oval shapes, as the case :may be, and preliminary deformationof margi- -nal portions thereof, where required, is eiiected. Either before or after the longitudinal seam is made in the fire tube, the concave end of each completed pass-over is inserted in the hole prepared for it in the fire tube, until bead Ii] engages th outer surface of the latter. Then the flanges 9 are bent up by a suitable crimping tool so as to clamp the wall of the fire tube between these flanges and the beads Ill. The longi tudinal seam for the fire tube is then completed if that had not previously been done, and cap 6 is applied.

Holes 2 in radiant shell 2 are large enough to allow the beaded outer ends of pass-overs 9 to pass freely through the same. If the longitudinal seam in this shell has not yet been completed, assembly of this shell on the pass-overs may be through wrapping it, as is were, around the fire tube. Where shell 2 has already been completed, it need only be sprung into a shape that is a little oval in cross section, to give it a transverse axis a little greater than the distance between the outer ends of the two upper pass-overs; thereby permitting the shell to slip down past the latter. Then the lower end of this shell is sprung at its lower end toproduce an oval shape whose long axis is at right angles to the oval shape still retained by the upper part of the shell. This permits the lower end of the shell to move down past the lower passover. continued and the angular position is adjusted until each hole therein registers with one of the pass-overs. When this occurs, the shell springs back into cylindrical shape, as the beaded outer ends of the pass-overs freely pass through said holes.

Shell 3 is applied in about the same manner as shell 2, although it need be sprung to a lesser extent because its normal diameter is equal to the distance between the beads on the outer ends of the two upper pass-overs, In other words, only the flange portions on the outer ends of the pass-overs need enter the holes in the shell, because the shell is intended to abut against the beads adjacent to these flanges. The flanges are then bent up to clamp the shell against the bands and fasten it rigidly to the fire tube The manner of applying flared ends 8 of the drum and shell 4 and 5 needs no explanation,

The downward movement of the shell is 6 except that the exhaust tubes l4 must be attached to shell A before the latter becomes a part of the completed drum.

It should further be noted that, although I prefer to make all joints through crimping, many of the advantages of my invention are retained even through some or all of such joints are welded.

I claim:

In a heater, a series of concentric shells permanently connected together into a single rigid unit, the innermost of said shells constituting a fire tube, two intermediate shells forming an annular heating drum, the drum being spaced apart from both the fire tube and the outermost shell to provide a plurality of annular openended spaces for the passage of air to be heated, an exhaust tube extending outwardly from the lower part of the drum through said outermost shell, a plurality of pass-overs extending radially between and fixed to the fire tube and the drum to connect their interiors together and serve to support the drum, two of the pass-overs being near the top and another being toward the bottom and diametrically opposite the exhaust tube, and a separate combined draft tube and burner housing conected to and closing the lower end of the fire tube.

HARTE H. DIGGINS.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 268,615 Brown Dec. 5, 1882 505,510 Dickinson Sept. 26, 1893 546,714. SchWa-b Sept. 24, 1895 556,899 Reader Mar. 24, 1896 646,996 Johnson Apr. 10, 1900 1,169,769 Carter Feb. 1, 1916 1, 01,957 Groten u s p 21, 31, 

